Magnetron beam switching tube in complementary switching circuit



Jan. 12, 1965 D. GLASER 3,165,663

MAGNETRON BEAM SWITCHING TUBE IN COMPLEMENTARY SWITCHING CIRCUIT Filed Oct. 24, 1962 m 22 e- T \0 0 Q E E INVENTOR.

DA V/D GLASER ATTORNEY United States Patent C 3,165,663 MAGNETRON BEAM SWITCHING TUBE lN COMPLEMENTARY SWITCHING CIRCUIT David Glaser, Greenbrook, N.J., assignor to Burroughs Corporation, Detroit, Mich., a corporation of Michigan 6 Filed Oct. 24, 1962, Ser. No. 232,798

7 Claims. (Cl. 3158.5)

This invention relates to electronic counting circuits and particularly to counting circuits using multi-position magnetron beam switching tubes as the counting elements thereof and useful in performing calculating functions.

Magnetron beam switching tubes are decimal devices which include an electron-emitting cathode and ten groups of electrodes, each of which is adapted to receive an electron beam from the cathode and toprovide an output signal therefrom. Each group of electrodes includes a target electrode which receives an electron beam and produces an output signal therefrom, an auxiliary collector electrode, a spade electrode which forms and holds an electron beam on its associated target electrode, and a switch electrode which may be used to switch an electron beam from one group of electrodes to the next to perform the counting operation.

Computers and calculators perform many diiierent operations, and for some operations, it is desirable to be able to obtain the complement of a first number, that is, the number which represents the difference between the first number and a selected numerical base. At the present time, the prior art does not provide simple and efiicient circuits which can be integrated in a calculating system and which provide complements of a number to a selected numerical base.

The objects of the invention concern the provision of an improved circuit for providing complements of a number to any selected numerical base. These objects are achieved by interconnecting the groups of electrodes of a multi-position tube so that, when the tube registers a particular numerical count, it may be immediately switched to register the complement of said count to the selected numerical base.

The drawing shows a schematic representation of a circuit embodying the invention and adapted to provide complements to a base of nine. The circuit utilizes a magnetron beam switching tube of the type sold by Burroughs Corporation and known as a BEAM-X switch. This type of tube is cylindrical in form but is shown schematically in linear form as tube 10 in the drawing. The tube 10 has an envelope 12 which contains a central cathode 14 and ten groups of electrodes spaced radially equidistantly from and surrounding the cathode. The groups of electrodes are numbered 0, 1, 9. Each group of electrodes includes a spade electrode 16 and a target electrode 20, with each spade electrode serving to form and hold an electron beam on its corresponding target electrode which provides an output signal from the beam. A switching electrode 22, known as a switching grid and used for switching an electron beam from position to position, is also included in each group of electrodes. An auxiliary electrode 23, which serves as a current collecting electrode, is provided between each target electrode and the adjacent leading spade electrode.

The tube 10 also includes suitable means (not shown) for providing an axial magnetic field which combines with electric fields within the tube to form an electron-beam and switch it from one group of electrodes to the next. Such means may be an external permanent magnet or internal magnets or the like. The direction in which an electron beam is urged, that is clockwise or counterclockwise, is called the leading direction, and is always the same and is determined by the orientation of the electric and magnetic fields.

3,165,663 Patented Jan, 12, 19 65 In the circuit shown, the cathode 14 is connected through a suitable resistor 24 to ground and to a source 25 of generally sawtooth waves 26 which are used to clear andreset an electron beam in tube 10. Eachspade electrode 16 is coupled through a spade resistor-27 to a spade bus 28 which is coupled to apositive D.C. power supply Vs of aboutSO volts. The target electrodes 20 are con nected through suitable load resistors 32 to a common target bus 34 which is coupled to a positive D.C. power supply Vt of about 200 volts. In addition, each target is connected to one of'the numeral cathodes 36 of a type 6844A indicator tube 37 "to provide a visible display of the operation of tube 10.' The anode 38 of tube 37 is suitably coupled to bus 34. i

According to the invention, each target electrode is also connected to the cathode of a diode 40, the anode of which is connected through a resistor 44 to a spade electrode 16 at one of the other positions in tube 10. Thus, in'a' decade counting tube such as tube 10 which is connected to provide nines complements, the 0 target, that is, the target at the 0 position, is coupled to the 9 spade, the 1 target is coupled to the 8. spade, the 2 target is coupled to the 7 spade, etc. Each target is also connected through a capacitor 46 to ground.

The switching electrodes 22 are connected in two sets with alternate electrodes in each set. Thus, the evennumbered electrodes are in one set, and the odd-numbered electrodes are in other set. Each set is coupled to one of the outputs 50 and 54 of the flip-flop 60 which thus applies switching pulses to tube 19 and causes an electron beam to switch from position to position. If desired, all of the switching grids might be connected to a single source of switching pulses.

The auxiliary electrodes 23 are suitably coupled to a positive D.C. power supply, for example, Vs. v

A source 64 of negative pulses is coupled to the target bus 34. This source may comprise a tube or transistor or any other suitable device.

In operation of the circuit of the invention, 'it is assumed that an electron beam is moving from position to position in tube 10 and it is desired to obtain the nines complement of the number of any particular tube position, e.g. posit-ion 2, at which the beam is located. When the beam is at the 2 position, a pulse is applied from source 64 to bus 34 to reduce this bus to about v. This pulse lowers the potential of anode 38 of indicator tube 37, and it also lowers the potential of all of the targets except the 2 target to about 100 volts; but the 2 target, which is receiving an electron beam, bottoms and is reduced to about 6 volts. This potential of about 6 volts is stored in the capacitor 46 which is coupled to the 2 target. All of the other capacitors are charged to about 100 volts. It is to be noted that the resistors 27 and 44 are selected to prevent the relatively low potential on capacitor 46' from being applied, at this time, to the complement spade, the 7 spade. Such a transfer of potential to the 7 spade would cause spurious switching of an electron beam to the 7 position.

Next, a pulse 26 from source 28 is applied to the cathode 14. The positive leading edge of pulse 26 raises cathode 14 to a positive potential, at which the beam flowing to the 2 position is cleared. The trailing edge of pulse 28 returns the cathode relatively slowly to normal operating potential, and, during this time of cathode return, the stored potential of about 6 volts on the 2 target is coupled through diode 40 and resistor 44 to the 7 spade electrode. All of the other spade electrodes are held at about 50 volts bytheir associated capacitors 46. This low potential applied to the 7 spade electrode alone causes an electron beam to reform in the 7 position and to provide a visual 7 indication.

In the same way, one can obtain the nines Complement of any number position to which an electron beam is flowing.

It is clear that, if the total number of tube positions are reduced or increased and the proper target-to-spade connections are made, then complements to substantially any numerical base may be obtained.

What is claimed is:

1. A counter circuit including an electron beam switching tube having a cathode and a plurality of groups of electrodes; each group including a target electrode which receives an electron beam and produces an output signal therefrom, a spade electrode which holds an electron beam on its associated target electrode, and a switching electrode which serves to switch an electron beam from one group of electrodes to the next;

each group of electrodes comprising a position to which an electron beam may flow;

each target electrode in one group of electrodes being connected to a spade electrode in a complementary group of electrodes;

voltage storage means coupled to each target electrode;

first circuit means coupled to all ofsaid target electrodes and operable to apply a selected potential to all of said target electrodes at the same time that an electron beam is flowing to one of said target electrodes;

said one target electrode being set thereby at a potential ditferent from the potential on all of the other target electrodes with the aid of its associated storage means;

second circuit means coupled to said tube for clearing and resetting an electron beam therein;

said potential on said one target electrode being applied to the spade electrode in the complementary group of electrodes whereby an electron beam forms and flows to said complementary group of electrodes, none of-the potentials on the other target electrodes being suitable for forming an electron beam.

2. The circuit defined in claim 1 wherein the potential on said one target electrode is lower than the potentials on all of the other target electrodes and of a suitable magnitude tov cause an electron beam to form in said tube.

3. The circuit defined in claim 1 wherein said storage means comprises a capacitor.

4. The circuit defined in claim 1 wherein the coupling path between a target electrode and the complementary spade electrode includes a unidirectional current flow device.

5. The circuit defined in claim 1 wherein the coupling path between a target electrode and the complementary spade electrode includes a diode.

6. The circuit defined in claim 1 wherein the coupling path between a target electrode and the complementary spade electrode includes a diode, and said storage means comprises a capacitor.

7. The circuit defined in claim 1 wherein said first circuit means comprises a pulse source,

and said second circuit means comprises a pulse source coupled to the cathode of said tube.

No references cited. 

1. A COUNTER CIRCUIT INCLUDING AN ELECTRON BEAM SWITCHING TUBE HAVING A CATHODE AND A PLURALITY OF GROUPS OF ELECTRODES; EACH GROUP INCLUDING A TARGET ELECTRODE WHICH RECEIVES AN ELECTRON BEAM AND PRODUCES AN OUTPUT SIGNAL THEREFROM, A SPADE ELECTRODE WHICH HOLDS AN ELECTRON BEAM ON ITS ASSOCIATED TARGET ELECTRODE, AND A SWITCHING ELECTRODE WHICH SERVES TO SWITCH AN ELECTRON BEAM FROM ONE GROUP OF ELECTRODES TO THE NEXT; EACH GROUP OF ELECTRODES COMPRISING A POSITION TO WHICH AN ELECTRON BEAM MAY FLOW; EACH TARGET ELECTRODE IN ONE GROUP OF ELECTRODES BEING CONNECTED TO A SPADE ELECTRODE IN A COMPLEMENTARY GROUP OF ELECTRODES; VOLTAGE STORAGE MEANS COUPLED TO EACH TARGET ELECTRODE; FIRST CIRCUIT MEANS COUPLED TO ALL OF SAID TARGET ELECTRODES AND OPERABLE TO APPLY A SELECTED POTENTIAL TO ALL OF SAID TARGET ELECTRODES AT THE SAME TIME THAT AN ELECTRON BEAM IS FLOWING TO ONE OF SAID TARGET ELECTRODES; SAID ONE TARGET ELECTRODE BEING SET THEREBY AT A POTENTIAL DIFFERENT FROM THE POTENTIAL ON ALL OF THE OTHER TARGET ELECTRODES WITH THE AID OF ITS ASSOCIATED STORAGE MEANS; SECOND CIRCUIT MEANS COUPLED TO SAID TUBE FOR CLEARING AND RESETTING AN ELECTRON BEAM THEREIN; SAID POTENTIAL ON SAID OEN TARGET ELECTRODE BEING APPLIED TO THE SPADE ELECTRODE IN THE COMPLEMENTARY GROUP OF ELECTRODES WHEREBY AN ELECTRON BEAM FORMS AND FLOWS TO SAID COMPLEMENTARY GROUP OF ELECTRODES, NONE OF THE POTENTIALS ON THE OTHER TARGET ELECTRODES BEING SUITABLE FOR FORMING AN ELECTRON BEAM. 